Brand New Tacoma with Brake Failure

OP stated the techs said there were no logs of any issues, other than a break and accelerator pedal pushed simultaneously. There is a lot of talk on here about computers going crazy causing break failure. MY POINT is that its not computer related.

 

Unless the ECU is the problem. DTC logging and brake function testing assume the skid control ECU is operating normally. I don't what the procedure is to self test the ECU for failure or firmware issues, it may be swapping ECUs with another or known good.

 

I find this quite disconcerting. That black box should only hold about 20 seconds of info during a crash, not a whole history of the vehicle actions (like the Progressive/Nationwide insurance trackers do).

http://www.usatoday.com/story/tech/...2/26/keep-your-car-black-box-private/20609035

 

ECU isnt going to cause the brake pedal to go to the floor.

 

It could if it's opening the ABS solenoid out of sequence.

 

Correct. Often for "safety" type systems like brakes, they don't design any system with the ability to prevent the brakes from working.

 

Which is why I asked if the parking brake is working. That's a fail safe that does not rely on the hydraulic or electronics.

And my assumption is that it doesn't have to be a system-wide failure, one wheel opening might be enough pressure loss such that the pedal travels too far. VSC or TRAC activating without the ABS pump running seems like it could do something like that. The skid control ECU also uses steering wheel angle, yaw, throttle position, even the engine parameters to decide what to do. There are several sensors and a lot of connectors involved.

I'm just suggesting that if it's something like a master cylinder or caliper or wheel cylinder then it should be relatively obvious. Bleed them, do the car on/off pedal test for a seal, etc. I have to think that the parts that haven't changed in 60 years still work the way they always have.

 

Subd

 

If the problem is internal to the ABS unit, it wont be an obvious and easy find. I dont know whether the ABS controller records problem or faults with an internal issue or failure.

 

OP, you need to start tracking what road/s this happens on and the surface type and smoothness [or lack of smoothness] and weather conditions. I'm betting that ABS activates/]or is defective] far to easily on bumps and releases hydraulic pressure cutting stopping force [all ABS really does in a hard stop situation is allow you to continue to steer by cutting brake pressure and not allowing wheel lockup]

I'm less then impressed myself with the brakes [and how poorly modulated they are in normal useage] on my 2015 TRDOR, the ABS/boost program seems to have been done using Amish computer programmers and drivers. I split driving time between an almost 19 year old GMC Sonoma and a 2015 Taco and I find it incredulous that something coming up on 2 decades old still has a better modulated ABS and braking system. No, it won't stop as quickly or in as short a distance but damn it, at least I don't have to think about foot pressure on the brake pedal and the damn thing over or underbraking severely with a very slight variation of pedal pressure, the Sonoma is very linear in pressure and thus, intuitive in normal driving.

 

It apparently only records a short period after an event, 20 seconds I think someone posted. If that's the case the truck needs to be shut down immediately after it happens and not restarted, at least since it seems the dealers are never able to reproduce it, of course.

 

If you get it back maybe you could get it to act up on some country road driving slow and use emergency brake to stop and KEEP your foot to floor with brake pedal and take pic with your phone. yea its crazy ?

 

Yeah, I have no idea about the length of data recordings. It would seem that if a known fault/issue occured it would store as a problem, similar to a check engine light code. If it doesnt recognize a problem it may not record the issue at all. Again, Im speculating as I dont know about the data recorders.

 

Operational faults (such as selecting reverse at speed, applying brakes and throttle simultaneously, etc.) are recorded and saved until cleared. A continuous loop is recorded of all parameters and is continuously written over but saved if airbags are deployed. These parameters are speed, throttle demand and opening, steering angle, abs engagement, etc., and much more. As moondeath says there has to be a mechanical problem for the brake pedal to go to the floor. Emergency brake is a completely different mechanical system that doesn't use hydraulics and has nothing to do with operational brakes thus irrelevant.

 

Sure it's related, looking for sticky or out of adjustment rear brakes. You also force the adjusters to ratchet by using the parking brake or stepping on the brakes while rolling backwards. If the parking brake handle pulls out/up just a few clicks and engages solidly then you can begin to eliminate the drums and rear shoes and cylinders potentially, too. If the parking brake feels weak then the rear brakes may be traveling too far, which can cause a low pedal. Think about how they feel after you do a rear brake job and the shoes are still pulled in all the way. The pedal goes straight to the floor until you operate the parking brake a thousand times.

 

The possible issues in 2008 FSM under low or spongy pedal:

1. Fluid leakage in brake system
2. Air in brake system (w/ VSC)
3. Air in brake system (w/o VSC)
4. Piston seal (Worn or damaged) (2WD)
5. Piston seal (Worn or damaged) (4WD and Pre-Runner)
6. Cylinder cup
7. Rear brake (Shoe clearance out of adjustment)
8. Brake master cylinder (Faulty) (w/o VSC)
9. Hydraulic brake booster (Faulty) (w/ VSC)
10. Booster push rod (Out of adjustment)

 

FWIW, I'm a left foot braker when driving automatics so, it's seems more than likely I've had momentary pressure on both the brake and throttle at the same time and I've never had a brake issue. The whole brake system should be independent of everything else except for needing the engine to be running for power assist.

 

It sounds like a master brake cylinder to me, but only because I’ve seen this problem a couple of times at max on one vehicle without ABS and one with ABS.
I would rule air out because I can’t recall ever seeing a hard brake pedal with air in the system.
But if the brake feels spongy, then yes air is fair game. But this (air) ought to be ruled out by now at the dealer.

But I would still suspect the hydraulic modulator and ECU module.

If it would happen to me, and If I could react fast enough, I would put it in neutral, pump the brakes quickly while pulling up on the emergency brake handle.
I would listen to see if the engine is in fast idle, or wot (wide open throttle).
If the vehicle comes to a very quick stop, I would suspect some type of computer failure, but if it comes to a stop slowly, I’d concentrate my efforts on the entire brake system.

Give the service rep as much info as possible, write everything you can think of that you observed at the time, and safe-keep a copy for future reference.
It helps to practice these steps, as this can happen with any vehicle.

Stay safe
Cheers!

 

I think you need to do more reading on the outcome of the "Toyota Unintended Acceleration" outcome. To make this easier for you, I am going to attach one article on it. A patrolman and his entire family died because Toyota was busy doing exactly what you are telling me I need to allow them to do.... SEE IT THEIR WAY? BE MORE UNDERSTANDING? Pardon me for saying so but F-THAT. All the floor mats that killed people and the all the hiding the recalls they did that resulted in so many injuries and death. Then to boot, there was in fact a sticky pedal problem that nobody wanted to talk about. 1.2 Billion dollars later and I need to see it from their point of view. They have done nothing to make me feel safer. They could have bought that vehicle back and sold it used for more than I paid for it and resold me another. So your answer is NO... I will not be more understanding.

And here is your article:


Car manufacturer Toyota has agreed to pay a staggering $1.2 billion to avoid prosecution for covering up severe safety problems with “unintended acceleration,” according to court documents, and continuing to make cars with parts the FBI said Toyota “knew were deadly.”

A deferred prosecution agreement, filed today, forced Toyota to “admit” that it “misled U.S. consumers by concealing and making deceptive statements about two safety related issues affecting its vehicles, each of which caused a type of unintended acceleration.”

Toyota “put sales over safety and profit over principle,” according to FBI Assistant Director George Venizelos.

“The disregard Toyota had for the safety of the public is outrageous,” Venizelos said. “Not only did Toyota fail to recall cars with problem parts, they continued to manufacture new cars with the same parts they already knew were deadly. When media reports arose of Toyota hiding defects, they emphatically denied what they knew was true, assuring consumers that their cars were safe and reliable… More than speeding cars or a major fine, the ultimate tragedy has been the unwitting consumers who died behind the wheel of Toyota vehicles.”

ABC News first reported the potential dangers of unintended acceleration in an investigation broadcast in November 2009. The report said hundreds of Toyota customers were in “rebellion” after a series of accidents were apparently caused by the unintended acceleration. Two months before, Highway Patrolman Mark Saylor and three members of his family had been killed after the accelerator in his Lexus had become stuck on an incompatible floor mat. Saylor was able to call 911 while his car was speeding over 100 miles per hour and explain his harrowing ordeal right up until the crash that ended his life.

EXCLUSIVE INVESTIGATION: Runaway Toyotas

At the time of the first ABC News report, Toyota attempted to assure its drivers that the incidents of sudden acceleration without warning were solely caused by floor mats becoming stuck on the gas pedals or driver error. But already other customers were complaining of similar problems with sudden acceleration, but some had nothing to do with the floor mats and they maintained they weren’t to blame either.

ABC News published dozens of reports in the following months as Toyota said it investigated and announced massive recalls to address the accelerators being stuck under floor mats – repeatedly assuring drivers that the problem had been taken care of. But today Toyota admitted that the recalls did not cover all the cars they knew were in danger and said that they also concealed another cause of sudden acceleration they had found during their investigations – “sticky” pedals, which refers to the accelerator getting stuck partially depressed.

In December 2009, the court records showed the company responded to “media accusations that it was continuing to hide defects in its vehicles” by publishing a statement on Toyota’s website saying the company “has absolutely not minimized public awareness of any defect or issue with respect to its vehicles [and] [a]ny suggestion to the contrary is wrong and borders on irresponsibility.”

Toyota only announced the issue with the “sticky” pedals, along with another massive recall, just minutes before an ABC News report on “World News” in January 2010 told the story of one driver whose Toyota Avalon took off suddenly on the highway.


The driver, Kevin Haggerty, credited ABC News with saving his life because he had seen a previous report that described what to do in the event of sudden acceleration. By shifting back into neutral, and back into drive when necessary, Haggerty was able to prod his broken vehicle to the dealership, where he said employees there saw that his problem with unintended acceleration firsthand had nothing to do with his floor mat.

However, Haggerty maintained that his sudden acceleration problem was not caused by a sticky pedal either. Regardless, today court documents showed Toyota knew about the sticky pedal problem in other Toyota models months before the recall and decided not to disclose it to regulators or the public.

For other drivers, it was already too late. In addition to deaths like the Saylors linked to unintended acceleration, a Minnesota man was serving an eight-year prison sentence for vehicular manslaughter when evidence emerged suggesting he could have been a victim of Toyota’s acceleration problem. After serving two years in prison, Koua Fong Lee was released and charges against him were dropped in 2010.

Earlier that year, an unidentified Toyota employee appeared to realize the dangerous game the company was playing.

“Idiots! Someone will go to jail if lies are repeatedly told. I cannot support this,” the unidentified employee said after a meeting between Toyota and regulators in January 2010, according to court documents.

Instead of jail, the company is now on the hook for the massive $1.2 billion fine, which U.S. Attorney General Eric Holder said was the largest penalty of its kind for an auto manufacturer. The money is due by March 25.

“Toyota confronted this public safety emergency as if it was a public relations problem,” Holder said.

A senior Justice official added that Toyota made "blatant misrepresentations" in what he called a classic case of corporate culture that favored the seemingly easy way out instead of paying the cost and doing the right thing.

"The cover up is always going to be worse than the original sin," the official said.

In a statement posted on its website, Toyota said that at the time of the recalls the company “took full responsibility for any concerns our actions may have caused customers, and we rededicated ourselves to earning their trust.”

“In the more than four years since these recalls, we have gone back to basics at Toyota to put our customers first,” said Christopher Reynolds, chief legal officer of Toyota Motor North America. “We have made fundamental changes across our global operations to become a more responsive company – listening better to our customers’ needs and proactively taking action to serve them.”

“Entering this agreement, while difficult, is a major step toward putting this unfortunate chapter behind us. We remain extremely grateful to our customers who have continued to stand by Toyota. Moving forward, they can be confident that we continue to take our responsibilities to them seriously,” Reynolds said.

 

Youre getting defensive and pissy. What I was pointing out was that there was a huge investigation into the conputer causing unintended acceleration. NASA tried to replicate to no avail. Here is an article for you.



http://usdotblog.typepad.com/secret...-of-unintended-acceleration.html#.V51VRvT3anM